C. Y. Roger Chen

Design of a multimedia object-oriented DBMS

The emerging multimedia information (such as video, image, voice, graphics) services have imposed many new requirements and research considerations on the design of database management systems (DBMSs). Conventionally, a multimedia DBMS is designed by developing a multimedia presentation layer on top of a pre-existing object-oriented DBMS (which can be truly object-oriented or relational-based), such that the core of the DBMS was developed earlier independent of the design of the multimedia presentation layer. Due to the fact that multimedia capabilities are not actually embedded in the DBMSs, such systems tend to provide only a rather limited set of functionalities in multimedia and are not satisfactory in supporting multimedia applications. This paper describes some key features of a multimedia object-oriented DBMS that is currently being developed. In this system the DBMS is carefully redesigned to provide special multimedia capabilities, such that the mismatch between the DBMS and the multimedia application layer can be eliminated. In particular, this paper will focus on unique multimedia capabilities including multimedia object modeling, video data management, and distributed collaboration.

Dual Eulerian Properties of Plane Multigraphs

A plane multigraph is said to be dual Eulerian if both itself and its dual contain an Euler path or circuit and the Euler paths have corresponding edge sequences. In this paper several properties of plane multigraphs are derived, and a necessary and sufficient condition for a plane multigraph to be dual Eulerian is given. Although the necessary and sufficient condition for a multigraph to be Eulerian is somewhat trivial, the necessary and sufficient condition for a plane multigraph to be dual Eulerian is not. Nevertheless, the question of whether or not a plane multigraph is dual Eulerian can be answered in time proportional to a linear function of the number of edges of the graph, and an algorithm that answers this question is presented in this paper. This theory can be applied to the layout synthesis of functional cells for Complementary Metal-Oxide Semiconductor Very Large-Scale Integrated circuits.

A Markov-modulated Bernoulli process approximation for the analysis of Banyan Networks

The Markov-Modulated Bernoulli Process (MMBP) model is used to analyze the delay experienced by messages in clocked, packed-switched Banyan networks with k x k output-buffered switches. This approach allows us to analyze both single packet messages and multipacket messages with general traffic pattern including uniform traffic, hot-spot traffic, locality of reference, etc. The ability to analyze multipacket messages is very important for multimedia applications. Previous work, which is only applicable to restricted message and traffic patterns, resorts to either heuristic correction factors to artificially tune the model or tedious computational efforts. In contrast, the proposed model, which is applicable to much more general message and traffic patterns, not only is an application of a theoretically complete model but also requires a minimal amount of computational effort. In all cases, the analytical results are compared with results obtained by simulation and are shown to be very accurate.

Transistor chaining in static CMOS functional cells of arbitrary planar topology

A technique for chaining the transistors in the layouts of static CMOS leaf cells is presented and analyzed. This new method is superior to existing techniques, since it can operate on a more general class of circuits and is very efficient. It is shown that the layout width of a CMOS leaf cell can be significantly reduced (nearly 40% in the average case) by transistor chaining. Moreover, more than half of the switching functions of four variables have optimal CMOS circuit implementations with non-series/parallel topologies. Therefore, the use of non-series/parallel circuits can have a positive global impact on layout area and performance. The transistor chaining technique presented in this paper produces the optimal solution for 82.5% of the circuits tested, and has linear time complexity.

Resource management issues of a video server

A video-on-demand system in a distributed environment relies on a video server that simultaneously provides video services to multiple clients and guarantees the quality of service (QoS) for each client. Because video data is categorized as continuous media, which has an implied dynamic temporal dimension, resource management of a video server has to be specially designed to meet new requirements. In this paper we develop the policy and the mechanism of resource management for implementing an MPEG- based video server that supports common VCR functionality. Our goal is to maximize the number of video streams to clients, while maintaining the quality of service of each video stream, under the limitation of system resources available on a workstation. We first define the policy and the QoS parameters for different video services. Then, we describe the mechanisms of admission control and resource control to efficiently implement the policy and guarantee the QoS for video services. A dynamic approach of resource reservation dealing with state change is also presented. The major contribution of this paper is to present a framework that integrates CPU/disk/network scheduling and memory management for video services. Under such a framework, we can manage system resources and optimize individual resources systematically.

Efficient application-independent visualization engine for information with complex data structure

A novel layered visualization model is proposed to provide a systematic approach for visualizing and manipulating information with complex structure. A heterogeneous multiple level composite container type concept is introduced to model any arbitrary complex data structure. The necessary visualization and manipulation strategies are also provided within the model. Based on the model, an efficient application-independent visualization engine has been designed and implemented. A type wrapper concept is used to provide a general application interface. Applications can easily interact with the visualization engine by registering application-dependent type wrappers into the engine. THE engine has been sued as the graphical interface to a distributed object-oriented multimedia database management system.

New architecture for MPEG-2 real-time encoding

A new architecture for real-time MPEG-2 encoding/decoding is presented in this paper. This architecture is based on an array of TI MVPs. The main feature of this architecture is its programmability. The inherent parallelism of the MPEG-2 algorithm is investigated in order to map it to the processor array. An I/O algorithm for the major encoding function, motion estimation, is developed to demonstrate the possibility of overlapping processing and I/O.

Performance analysis of communications in static interconnection networks

We present a model, based on a network of DX/D/1 queues, to predict the communication performance of static interconnection networks under various communication patterns. Our model predicts delay time distributions in the links as well as the first and second moments of the overall delay time of messages in the system. These predictions are verified by the results of simulations.